Timepiece with a calendar mechanism



United States Patent O 3,495,395 TIMEPIECE WITH A CALENDAR MECHANISM Horst Fehrenbach, Seedorf, Wurttemberg, and Robert Wolber, Lauterbach, Wurttemberg, Germany, assignors to Messrs. Gebruder Junghans G.m.b.H., Schramberg, Wurttemberg, Germany, a corporation of Germany Filed Dec. 20, 1968, Ser. No. 785,490

Claims priority, applctilolgrmany, Dec. 29, 1969,

Inf. c1. G6411 19/24 U.S. Cl. 58-4 8 Claims ABSTRACT F THE DISCLOSURE The invention relates to a timepiece, such as a table or wall clock, having a calendar mechanism for showing the date, and wherein, as is customary, the day star wheel is located between the dial and the clockworkmovement, the date finger of the date stepping wheel cooperating with the internal teeth of the internal teeth of the day star wheel to advance the latter one step every 24 hours. At least one stationary pawl cooperates with these internal teeth to hold the day star wheel in the correct position with respect to a physical reference, such as an index mark or a window.

The object of the invention is to produce a date calendar mechanism of the simplest construction, "which is suitable for adding to timepieces as presently designed, which is Very shallow, so that the depth of the clockworkmovement is not appreciably increased, and which is simple and inexpensive to manufacture.

Further objects will be apparent from the following description when considered in connection with the accompanying drawing in which;

FIG. 1 is a front view of the calendar mechanism, taken along line I-I of FIG. 2, in the direction of the arrows,

FIG. 2 is a sectional view taken along line IIII of FIG. l, in the direction of the arrows,

FIG. 3 is a side sectional view taken along line III-III of FIG. l, in the direction of the arrows,

FIG. 4 is a detail perspective View of the pinion connection between the hour wheel and the date stepping wheel; and

FIG. 5 is a perspective view on a larger scale of the date stepping wheel.

The dial of the timepiece is illustrated only to the extent necessary to understand the invention. The shallow, disc-like case 11 for the date calendar mechanism is located behind the dial, and is made of an elastic material. The case embodies a rim 11a that contacts the dial, which thus serves as the case cover. The day star wheel 12, having a guide rib 12a that contacts the dial 10, is located within the cavity formed by the case 11. The rear face of the day star wheel also incorporates a circular guide rib 12b, which acts as a radial guide in cooperation with a circular guide step 11b provided in the case back for guiding and centering the day star wheel. The day star wheel 12 has the usual internal teeth 12c that cooperate with the stationary elastic pawls 11e, which are formed out of a hub-shaped central wedge or prominence or hub 11d embodied in the back of the 3,495,395 Patented Feb. 17, 1970 case 11. The pawls 11e hold the day star wheel 12 in the correct positions, so that the days of the month, as 31, successively appear in the dial window 10a. In the embodiment shown, two diametrically opposite pawls are used, although any other suitable number of pawls can be incorporated.

The calendar case 11 if xed to the front part of the case 13 for the clockwork-movement 14 by a hollow screw 15, through the hole of which project the cannon pinion 16 and the pipe 17 of the hour wheel. Additional means for fixing the case 11 are indicated by the reference numberal 18.

The internal teeth 12c of the day star wheel 12 also cooperate with a date stepping wheel 19, which turns on a pin 11e formed out of the back of the case 11 and completes one revolution every 24 hours. The stepping wheel 19 is drivingly connected to the hour wheel 20 (see FIG. 3) by a pinion 21 forming a part of the movement, which is not further shown. This pinion is mounted on the bottom plate 23 by a pivot 22, the other end of the pivot mounting a pinion 24 that meshes with the stepping wheel 19. The latter has a hollow h ub 19a to which is fixed a spiral stepping day-finger 19h having a nose 19e. An opening 19d in the wheel 19 permits the day finger 19b to .move radially. The nose 19c of the pawl is thickened (see FIG. 5) so that it projects beyond the plane of the wheel 19, since the latter is positioned behind the day star `wheel 12, as shown in FIG. 3. The day finger 19b is free to give way in either direction of rotation, when the day star wheel 12 is turned by hand.

In the case 11, the day star wheel 12, and the stepping wheel 19 are all advantageously made of a suitable synthetic plastic, the stepping wheel being injection molded to produce a nished article. The lower part of the case 11 can be truncated at 11f and provided with an index mark 11g for the date numbers 11b that appear along the edge of the rear face of the day star wheel. With this arrangement, the user can easily set the timepiece to the correct date from the back. Wall clocks which have a plate that is not next to the wall can be set from the front by supporting the plate. The outer edge of the day star wheel is advantageously provided with teeth 11i, each tooth bearing a respective date.

The calendar mechanism shown in FIGS. 1 to 3 is intended for a timepiece without an alarm. If the timepiece is provided with an alarm arrangement, the hour wheel 20 must drive both the date stepping wheel 19 and the alarm setting wheel, not shown. In order that the alarm setting `wheel will make one complete revolution every 12 hours with a conventionally designed dial, the pivot 22 (see FIG. 3), driven by the hour `wheel 20, can be provided with a pinion 50 (see FIG. 4), `which meshes with the alarm setting wheel. A further pinion 51 can be coupled to the pinion 50 by a claw coupler 51a. The pinion 51 has half the number of teeth and .meshes with the operating wheel 19.

We claim:

1. A timepiece with a calendar mechanism for showing the date, comprising a day star wheel located between a dial and a clockwork-movement, internal teeth on said day star wheel, a date stepping wheel which makes one complete revolution every 24 hours, a date finger in said date stepping wheel for cooperation with the internal teeth of said day star wheel for advancing said day star wheel in step like manner, at least one stationary pawl cooperating with the internal teeth of said day star wheel for holding said day star wheel in the correct position with respect to a physical reference, a shallow and elastic disclike case for the calendar mechanism, a central hubshaped prominence in said case, at least one pawl being mounted on said prominence, and cooperating with the .teleth of thestar wheel a circular guide step in said case,

a circular guide rib on the day star Wheel for cooperation with said guide step to center and guide said day star wheel, a cover for said case, a rim on said case to contact said cover, a pin for mounting said date stepping Wheel free to rotate, and said date linger being elastic and free to move in either direction of rotation of said day star wheel.

2. A timepiece according to claim 1, in which said cover also serves as a dial of the timepiece.

3. A timepiece according to claim 1, in Which said pin is integral with said case.

4. The timepiece according to claim 1, in which the case, the day star wheel and date stepping wheel are made of synthetic plastic.

v5. T he timepiece according to claim 1, in which a plurality of said pawls are provided symmetrically positioned about the center defined by said date star wheel.

6. The timepiece according to claim 1, in which date numbers are providing along the outer edge on the rear 4 face of said day star wheel, and said case having means for making said date numbers visible and for facilitating their reading.

7. The timepiece according to claim 1, in which teeth are provided on the day star wheel, each said tooth bearing a respective date number.

8. The timepiece according to claim 1, in which teeth are provided on the outer edge of said day star wheel, each said tooth bearing on a respective date number.

References Cited UNITED STATES PATENTS 2,650,467 9/1953 Faure 58-58 2,764,828 10/1956 Wolaver 40-115 RICHARD B. WILKINSON, Primary Examiner E. C. SIMMONS, Assistant Examinerv U.S. Cl. X.R. 58--58 

